• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.574-576
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• 2005

유무선 통합망 환경에서 TCP는 무선망에서의 통신오류 밀 핸드오프를 혼잡으로 인한 패킷 손실로 간주하여 혼잡제어 메카니즘을 동작시키기 때문에 네트워크의 전반적인 효율을 저하시킨다. 이러한 문제점을 해결하기 위한 방안으로 무선망에서의 TCP 성능을 개선하기 위한 연구가 다양하게 진행되어 오고 있다. 그 중에서 Snoop 프로토콜은 종단간의 의미 구조를 유지하면서 무선망의 패킷 손실을 지역 재전송을 통하여 최소화하는 방식으로 통신오류에는 좋은 성능을 보여주지만, 대량의 무선 데이터 유입시 buffer overflow가 발생할 가능성이 높다. 따라서 본 논문에서는 버퍼관리 기법을 이용하여 buffer overflow 상황을 미연에 방지하여 불필요한 혼잡제어 메카니즘을 호출하는 것을 방지하면서 네트워크의 전반적인 효율을 향상시키는 방안을 제안하였다.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.581-584
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• 2008

This study analyzed activity of rockfall and its effect factor by the shape and mass. We performed research on the kinetic energy distribution, velocity and bounce height according to the rockfall characteristics using rockfall simulation program in cut-slope. In addition, this study discussed how to utilize kinetic energy and bounce height of rockfall for efficient establishment of rockfall prevention fence which is a countermeasure to cut-slope.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.166-167
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• 2015

단열재를 생산하는 회사에서는 대부분 유기단열재를 사용하고 있다. 커튼윌 시스템은 경제적이면서 성능이 우수하지만 불연성이지 않다. 따라서 근래에 안전사고가 많아지고 있어서 타지 않는 무기 단열재가 필요하다. 또한 안전과 단열효과 및 소비자가 요구하는 친환경적인 무기단열재가 필요하므로 불연성 무기단열재의 개발이 시급하다. 본 논문은 무기단열재의 문제인 흡수성을 실험하기 위하여 가습기를 이용하여 흡수성 실험을 하였고 경량골재인 펄라이트와 바인더를 섞고 흡수방지제로 처리한 샘플과 그렇지 않은 샘플의 흡수율을 측정하여 에너지 효율 지속성 단열재의 기술연구를 목표로 한다.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.292-300
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• 2016

Diverse and comprehensive countermeasures were established to prevent water pollution in coastal areas such as constructed wetlands(CW).This study was conducted to assess the water quality improvement through CW constructed along the shoreline of Hwaseong coastal reservoir. The CW is located in Hwaseong-si, Gyeonggi-do and consisted of a forebay and a wetland. The CW was monitored twice during rainy days and 10 times during dry days. The monitoring results indicated that in and out flowrates were highly correlated with COD and TN loads. COD, TN and TP concentrations in the forebay was lower during dry days than rainy days. However, concentration and mass removal efficiencies of COD, TN and TP were greater during rainy days. In addition, the volume flowing into the CW was less compared to the outflow during rainy days indicating that the CW efficiently reduced the runoff volume. The overall pollutant removal efficiency of the CW were at least 50% for TSS, 20 to 35% for TP, and 26 to 94% for TN. The data gathered may be used to improve the pollutant removal efficiency of the system in the future.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.168-175
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• 2010

During feeding oxidizer to the engine, vortices are occurred at lower dome of oxidizer tank inside by various working environments and external forces for liquid propellant feeding system of space launch vehicle. To eliminate the vortices or swirls Anti-Vortex Devices(AVD) shall be installed at inside lower oxidizer tank. Using the numerical analysis, we have confirmed the performance of AVD and analyzed the mass flow rate by feeding time and magnitudes of swirls on the free surface of oxidizer or exit surface according to the AVD number and length. Then we could derive the optimal design of the AVD number and length.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3A
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• pp.184-194
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• 2005

One of the most important factors that decide the overall performance of RFID system is anti-collision algorithm. By enhancing the anti-collision algorithm, we can increase the number of RFID tags that can be processed in unit time. Two anti-collision algorithms are most widely prevailed: one is ALOHA-based protocol and the other is a binary tree walking method, but these are still under research. In this paper, we suggest an anti-collision algorithm named AAC(Address Allocating and Calling) using pre-distributed random address, which is much faster and more efficient than existing ones. Finally, we evaluate our scheme using mathematical analysis and computer simulation.

• The Journal of the Korea Contents Association
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• v.5 no.1
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• pp.157-167
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• 2005

In this paper, we propose a new phantom protection method for multi-dimensional index structures. The proposed method uses a hybrid approach of predicate locking and granular locking mechanisms. The proposed mechanism is independent of the types of multi-dimensional index structures, i.e., it can be applied to all types of index structures such as tree-based, file-based and hash-based index structures. Also, it achieves low development cost and high concurrency with low lock overhead. It is shown through various experiments that the proposed method outperforms existing phantom protection methods for multi-dimensional index structures.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.671-676
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• 2009

Described here for the first time is an investigation on geometrical and electronic molecular structure of metol (N-methyl-p-aminophenol sulphate) as corrosion inhibitor of steel using density functional theory (DFT) calculations. Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap ((${\Delta}E$), Mulliken charges (($q_M$) and natural atomic (($q_n$) charge have been calculated both for gas and aqueous phases by using B3LYP/6-31G+(d,p) basis set. The relation between the inhibition efficiency and quantum chemical parameters have been discussed in order to elucidate the inhibition mechanism of the title compound.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.492-494
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• 2014

정보유출사고가 증가됨에 따라, 기업 및 기관 내 주요정보(개인정보 및 핵심기술)가 유출되어 큰 피해가 발생하고 있다. 이러한 정보유출 사고 중 대부분이 내부자에 의한 고의 또는 실수로 발생하는 경우가 대부분이다. 이를 방지하기 위해 다양한 보안 솔루션을 도입하여 운영하고 있지만 내부자에 의한 정보유출사고는 본인이 소유하고 있는 권한을 이용하여 불법적인 정보유출을 시도하는 것으로, 이러한 위험행동을 탐지하는 것은 쉽지 않다. 이를 해결하기 위해 기업 및 기관에서는 기 구축된 다양한 보안 솔루션을 통합하여 모니터링 할 수 있는 '내부정보유출방지 모니터링시스템'을 구축하고 있으며, 내부정보유출방지 모니터링을 위한 연구도 지속적으로 진행되고 있다. 따라서 본 논문에서는 중점관리 대상(고위험군) 선정을 통해 효율적인 내부정보유출방지 모니터링을 수행할 수 있도록 연구하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1564-1568
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• 2008

The anti-collision system is one of units for effectual operation and safety in crane operation. Most of the system have used ultrasonic to measure position and to prevent collision of crane. But, the anti-collision system using ultrasonic is fallen the reliability of performance by the change of temperature and humidity. Hence, this study proposes neural network applied to anti-collision system to improve accuracy and stability of the measured distance data, and we evaluate performance of the system. In results of experiments, the proposed method was seen that stability and accuracy of data are improved than that of the temperature compensation method.